This invention relates generally to archery bows and more particularly to compound archery bows and a system for mounting limbs to a riser of the bow.
Compound archery bows having a handle or riser portion with a pair of limbs extending from opposed sides or ends of the riser are well known. Typically to connect the limbs to the riser, a bolt or connector extends through the limb and into the riser.
After assembly of the bow, with the limbs under tension, it may be desirable to change the draw weight or force required to pull a draw string of the bow to its fully drawn position. To do this, the bow may be disassembled and a bow string of a different length provided to change the initial flex of the bow limbs, or the cap screw connecting the limbs to the riser may be loosened or backed out slightly to change the orientation of the limb relative to the riser and thereby change the initial loading of the limb. Notably, significant shearing forces are exerted on the bolt as the orientation of the limb relative to the riser is changed which greatly limits the degree to which the connector may be backed out or adjusted without shearing or breaking the connector. Therefore, the draw weight of a bow with only a connector extending through the limb and into the riser can only be adjusted a very minimal amount, if at all, after assembly of the bow.
In some bows, a separate steel, cylindrical pin is provided in the riser for each limb and threadedly receives the end of the connector extending through its associated limb and into the riser. The pins can pivot or rotate relative to the riser only in a single plane generally transverse to the axis of the pin to permit some relative pivotal movement of the connectors relative to the riser. This limits the shearing forces on the connectors within a limited range when they are backed out to adjust the draw weight of the bow. With the addition of the pins, the draw weight of the bow may be adjusted over a somewhat wider although still very limited range after assembly of the bow as compared to a compound bow without any pins.
The pins are generally cylindrical, formed of steel for high strength and are received in complementary bores in the riser and may each weigh up to one ounce or more which undesirably adds to the weight of the bow. Notably, the pins and the bores in the riser which receive them must be very accurately located in the riser to achieve their intended purpose. This increases the time and cost to manufacture and assemble the bow. Still further, the total range of adjustment of the draw weight of the bow is still limited even with the pins wherein the relative movement between the connectors and the limbs occurs at the end of the connectors within the riser and pin. Undesirably, each connector is received in a threaded blind bore in its pin which reduces the number of threads of the connector that are received in and retained by the riser. Accordingly, the extent to which the connector can be backed out to change the bow draw weight without stripping the connector or the threads in the bore of the pin, is limited.
A connector for adjustably mounting a limb of a compound archery bow to a riser of the bow has a connector, a first washer with a sliding surface and a guide surface complementary to and received adjacent to the sliding surface of the first washer and permitting the first washer to pivot in substantially any direction relative to the connector. In assembly, a threaded shank of the connector is received in a threaded blind bore in the riser and a head of the connector traps the first washer between the connector and the limb. The connector may be loosened or backed out of the riser to permit adjustment of the orientation of the limb relative to the riser to reduce the degree to which the limb is initially flexed and thereby adjust the draw weight of the bow. As the orientation of the limb is changed, the orientation of the first washer relative to the connector is likewise changed without changing the axial orientation of the connector or bending it which limits the shearing forces applied to L the connector and prevents it from being sheared or otherwise failing. Preferably, an insert which defines the guide surface is disposed within a generally concave recess of the washer between the washer and the head of the connector and is complementarily shaped to the recess to permit angular or pivotal movement of the first washer relative to the connector in substantially any direction.
The first washer preferably has a flat face adjacent to and preferably fully engaged by or flush against the limb of the bow in assembly. As the connector is displaced relative to the riser such that the orientation or position of the limb relative to the riser is changed, the flat face of the washer is maintained flush against the limb and the washer pivots with the limb relative to the connector to avoid placing undue stress on the connector. With this arrangement, the draw weight of the bow may be changed over a wide range without breaking or putting undue stress on the connector. If desired, a flat, annular second washer may be disposed between the limb and the washer. The second washer may be formed of a generally resilient or ductile material to reduce vibrations of the bow in use, and prevent damage to the limbs from the first washer. Alternatively, the head of the connector may defame the guide surface and may be shaped complementary to the sliding surface of the first washer to permit the first washer to pivot relative to the head of the cap screw without any insert between them.
Objects, features and advantages of this invention include providing a compound bow with a connector assembly for mounting the limbs of the bow to the riser which facilitates adjustment of the draw weight of the bow, permits the draw weight of the bow to be adjusted over a wide range after assembly of the bow, reduces the overall weight of the bow, prevents undue stress from being applied to a connector attaching the limb to the riser, provides improved engagement of the connector with the riser to more securely mount the limbs to the risers, eliminates pivoting of the connector relative to the riser, is of relatively simple design and economical manufacture and assembly and has a long, useful life in service.